Pierce punch



J. D. MAURER PIERCE PUNCH Feb. 15, 1966 2 Sheets-Sheet 1 Filed Oct- 9, 1963 INVENTOR. 7770s ,3. )fkzzrz? 7.

Feb. 15,

Filed Oct.

J- D- MAURER PIERCE PUNCH 2 Sheets-Sheet 2 United States Patent Ofifice 3,234,334 Patented Feb. 15, 19%6 3,234,334 PIERCE PUNCH James ll). Maurer, Detroit, Mich, assignor to Richard Brothers Punch Company, Detroit, Mich, a corporation of Maryland Filed Get. 9, 1%3, Ser. No. 315,M1 2 Claims. (Cl. 83-13ll) The present invention broadly relates to metal worlring apparatus and more particularly to an improved pierce punch incorporating an ejector mechanism therein which is selectively operable to maintain an ejector pin in a retracted inoperative position facilitating the sharpening of the cutting face of the punch as may be required from time to time.

Pierce punches of the so-called slug-shedder type incorporate an ejector mechanism therein which is adapted to facilitate dislodgment of a cutout slug from the cutting face of the punch. Such ejector means are necessary in many instances due to the tendency of the cutout slug to adhere to the face of the punch at the completion of punch stroke due to the magnetic attraction therebetween and/ or the presence of a thin film of oil between the surface of the slug and the cutting face of the punch. Conventionally, an ejector mechanism comprises a resiliently biased pin slidably disposed in a bore extending inwardly of the cutting face of the punch which is adapted to apply a separating force against the slug at the completion of a punching operation. The ejector pin in its normal projected position is disposed with its end extending beyond the face of the punch. The ejector pin moves toward the retracted position in response to contact of the punch face with the sheet stock to be pierced.

While the inclusion of such injector mechanisms in pierce punches have substantially eliminated the problems associated with the adherence of cutout slugs to the punch faces, their use has created a problem during the sharpening of the punch faces as is required from time to time during normal use. This problem is due to the ends of the ejector pins projecting from the punch face preventing accurate grinding of the punch face while can currently avoiding grinding or? the projecting ends of the ejector pins rendering them useless.

In order to overcome this problem, it has heretofore been common practice to remove the punch from the punch retainer and thereafter disassemble and remove the ejector pin therefrom prior to a grinding or resharpening of the punch face. Since the projecting distance of the end of the ejector pin beyond the punch face must be maintained within a reasonable range, it is also necessary to separately grind the end of the ejector pin each time the punch face is ground. It will be apparent from the foregoing that the removal, disassembly, and separate grinding of the punch face and ejector pin constitute a tedious, costly and inefficient mode of operation. This technique moreover is completely impractical for resharpening a complicated punch set comprising a plurality of punches mounted in a common punch retainer.

It has heretofore been proposed to include an aperture in the body of the punch through which a suitable pin can be selectively inserted so as to engage and retain the ejector pin in a retracted position enabling concurrent grinding of the face of the punch and the end of the ejector pin. It has been found in many instances however, particularly in multiple punch sets, that inadvertent dislodgment of the retaining pin occurs during the course of the sharpening operation whereupon the one or more ejector pins are inadvertently released resulting in interference in the grinding operation as well as the grinding oif of the projecting ends of the pins.

It is accordingly, a principal object of the present invention to provide an improved pierce punch incorporating an ejector mechanism therein which overcomes the problems and disadvantages associated with slug-shedder type punches heretofore known.

Another object of the present invention is to provide an improved pierce punch incorporating a novelejector mechanism therein which is selectively positionable in a fully retracted position facilitating the simultaneous sharpening of the end of the ejector and the cutting face of the punch without necessitating removal of the punch from the retainer for disassembly thereof.

Still another object of the present invention is to provide an improved pierce punch incorporating therein an irnprove-cl ejector mechanism which is of simple design, of simple and durable operation, and of economical manufacture and use.

The foregoing and other objects and advantages of the present invention are achieved by employing a resiliently biased ejector mechanism comprising a pin having an enlarged head portion thereon which is slidably disposed in a stepped bore extending inwardly from the cutting face of the punch, The head of the ejector pin and the periphery of the counterbore adjacent to the head are provided with coacting means which are selectively engageable so as to retain the ejector pin in a retracted position in re sponse to inward movement of the end of the ejector pin beyond a preselected point spaced inwardly of the punch face. The coacting means are simply disengaged releasing the ejector pin for movement toward its normally biased projected position by simply moving the ejector pin inwardly a second time beyond a preselected distance.

Other objects, features and advantages of the present invention will become apparent from the subsequent description, taken in conjunction with the accompanying drawings, wherein:

FIGURE 1 is a fragmentary vertical sectional View of a shoulder-type pierce punch incorporating an ejector mechanism constructed in accordance with one embodiment of the present invention and illustrating the head of the ejector pin along the line ll-]l of FIGURE 2;

FIG. 2 is a fragmentary enlarged transverse sectional view to the head portion of the ejector illustrating the coacting means therearouncl as shown in FIGURE 1 and taken along the line 2-2 of thereof;

FIG. 3 is a fragmentary side elevation View of the ejector illustrated in FIGURES l and 2;

PKG. 4 is a fragmentary side elevation view of an alternative satisfactory ejector from that shown in FIG- URE 3;

FIG. 5 is a fragmentary vertical sectional View of the head portion of the ejector constructed in accordance with still another embodiment of the present invention and illustratir: a modified form of the resilient means urging the ejector toward the fully projected position; and

FIGS. 6 through 9 inclusive are diagrammatic planar views of the enacting relationship of the engaging means on the head of the ejector and Within the body of the punch for providing selective retention of the ejector pin in a retracted position.

Referring now to the drawings and as may be best seen in FlGURE l, a typical shoulder-type pierce punch including a slug-shredder mechanism is illustrated which is removably mounted in a retainer 10 which in turn is fastened to a shoe 12 of the ram of a press (not shown) by means of machine screws lid. The punch comprises an elongated body formed with an annular shoulder 16 at the upper end thereof for engaging a corresponding shoulder of a stepped bore 18 formed in the retainer ill.

The lower end of the pierce punch is formed with a cutting face indicated at 20 from which a bore 22 extends inwardly and axially of the body of the punch. A second bore 24 extends inwardly from the opposite end asst,

(3 of the punch and is disposed in axial alignment and end communication with the bore 22. An annular shoulder 26 is formed at the juncture of the bores 22 and 24.

An ejector 28 as shown in FIGURES 1 and 2 col prises an elongated pin Ell having an enlarged head 32 at the upper end thereof which is adapted to be slidably disposed in the bores 22 and 24 for relative longitudinal reciprocation therein. The ejector 28 is biased toward a fully projected position as shown in FIGURE 1 by means of a coil spring 34 disposed within the bore 24 and having its upper end seated against a set screw 36 threadably engaged in the upper end of the bore 24 and seated at its lower end against a plunger 38 disposed in bearing contact against the head 32 of the ejector. As will be noted in FIGURE 1, the plunger is formed with an enlarged collar 40 for providing guided movement thereof within the bore 24. The upper end portion of the plunger 38 is provided with a cylindrical extension 42 for guidably maintaining the coil spring 34 in appropriate axial alignment. The lower end portion of the plunger 33 is formed with a cylindrical extension 44 of a reduced diameter which is adapted to be disposed in clearance relationship within a collar or sleeve 45 disposed within the lower end portion of the bore 24. It will be apparent from the arrangement as shown in F1.- URE 1 that the normal position of the ejector is as shown in FIGURE 1 with the head 32 of the ejector disposed in bearing contact against the annular shoulder 26 preventing further outward movement of the ejector in response to the biasing force of the spring During a punching operation, as the punch face 2% approaches the surface of the sheet material to be pierced thereby, the end of the pin 3%) makes contact with the sheet material causing the ejector 28 to move toward a retracted position wherein the end of the pin 3% is disposed fiush with the cutting face 2% of the punch. At the completion of the piercing movement of the punch, through the sheet, the biasing force of the spring 341 causes the ejector to move to the projected position effecting a dislodgement or shedding of the cutout slug. During the sharpening of the cutting face of the punch, it is also desired to retract the pin 3% to a position wherein the end thereof is flush with the cutting face of the punch in order that both the cutting face and end of the pin are ground simultaneously. The selective restraint of the ejector in a retracted position is achieved by coacting means on the head 32 of the ejector and around the inner circumferential surface of the sleeve 46 of a configuration as hereinafter described.

As shown in FIGURES 1 and 2 the head 32 of the ejector is provided with a plurality of circumferentially spaced radially projecting cams 48 which are adapted to coact with a series of longitudinally extending circumferentially spaced upper cams t positioned around the upper end surface of the sleeve 46 and a series of lower cams 52 and 52 which are disposed in longitudinally extending circumferentially spaced relationship around the lower edge of the sleeve 46. The relative relationship between the earns 48, 5t 52 and S2 is best illustrated in FIGURES 6-9. As will be noted, the upper and lower ends of the cams 48 are formed with angularly inclined surfaces 54 while the upper cams so are formed with angular surfaces 56 at the lower ends thereof and the upper ends of the earns 52, 52' are formed with angular surfaces 58, 58' respectively.

In the disengaged position as illustrated in FIGURES 1 and 2, the cams 48 on the head 32 of the ejector are disposed in sliding engagement between the adjacent side surfaces of the earns 52, 52. In this condition, the ejector is free to move inwardly to a retracted position where the end of the pin 3% is disposed flush with the cutting face 20 of the punch without effecting contact of the upper ends of the earns 43 with the cam surfaces of the upper cams St on the sleeve The guided coaction between the cams 43 and the cams 52, 52 further re- A stricts relative rotation of the ejector within the bores 22, 24.

When it is desired to lock the ejector in a retracted position such as prior to a sharpening of the punch face, a suitable pin indicated at 66) in FIGURE 1 which may comprise a nail or the end of a paper clip, for example, is disposed against the projecting end of the ejector caus ing it to move upwardly until the upper inclined surfaces 54 on the cams 48 contact the angular surfaces 56 on the upper cams Stl effecting a controlled indexing of the ejector in a manner as will now be described in connection with FIGURES 69.

As shown in FIGURES 6-9, the sleeve 46 and the peripheral surface of the head 32 of the ejector have been unrolled in a flat position to facilitate an understanding of the relative camming coaction provided thereby. In the normal released position, the cams .8 on the ejector are disposed in sliding engagement between the side edges of the cams 52, 52' as shown in solid lines in FIG- URE 6. In response to the upward movement of the ejector as provided by the insertion of a pin 66 against the end of the pin 30, the ejector moves upwardly to a position wherein the earns 48 coact with the cams 59 in a manner as shown in phantom in FIGURE 6. The coaction between the angularly inclined surfaces 54 of the cams 48 shown in phantom and the lower inclined surfaces 56 of the cams shown in solid lines effects an angular turning movement of the ejector toward the right as viewed in FIGURE 6 until the earns 43 are positioned between the gaps provided between adjacent cams 5ft. Continued further inward movement of the ejector as provided by the inward thrust of the pin 6t) results in the cams 48 on the ejector assuming the position as shown in solid lines in FIGURE 7.

A release of the inward thrust by the pin 6i) causes the coil spring 34 to move the ejector downwardly to a position wherein the cams 48 as shown in phantom in FIGURE 7, are disposed with their lower angular surfaces 54 in contact with the angular surfaces 53 of the earns 52'. Further downward biased movement of the ejector in response to the force applied by the spring 34 causes the ejector to rotate as the result of the angular sliding movement of the cam 48 relative to the earns 52' until an engaged position is attained as shown in solid lines in FIGURE 8. As shown in FIGURE 8, further rotary movement of the cams 48 relative to the cams S2 is prevented by the blocking coaction between the side edges of the cams 48 and the earns 52. In this position the ejector is retained in a retracted position with the end of the ejector pin 30 disposed substantially flush with the cutting face of the punch.

At the completion of a resharpening of the cutting face, the ejector pin is released by again inserting a suitable pin such as the pin 66 against the end of the ejector pin 3i? effecting upward movement of the ejector in opposition to the coil spring 34. Such upward movement causes the cams it; on the head of the ejector to move from the position as shown in solid lines in FIGURE 8 to the position as shown in phantom. Further inward thrust by the pin so against the end of the ejector effects relative rotation of the ejector in response to the coaction between the inclined cam surfaces 54* at the upper end of the cams 43 and the inclined cam surfaces at the lower end of the cams Sit whereupon the earns 48 assume a position as shown in solid lines in FIGURE 9 wherein they are disposed between the cams 5% In this position, a release of the inward thrust as applied by the pin enables the resilient biasing force of the coil spring 34 to cause the ejector to move downwardly from the position as shown in solid lines in FIGURE 9 to a position as shown in phantom wherein coaction between the lower angular inclined surfaces 54 on the cams 48 and the upper inclined surfaces 53 on the earns 52 effect rotation to the right as viewed in FIGURE 9 wherein the cams 43 drop downwardly between th earns 52, 52' to a position as originally shown in soild lines in FIGURE 6. In this position the ejector is in a released normal condition wherein its end projects beyond the cutting face of the punch as shown in FIGURE 1. Reengagenient of the ejector is simply achieved by again inserting the pin 69 causing inward movement of the end of the ejector pin a preselected distance inwardly beyond the cutting face of the punch.

An alternate satisfactory version of an ejector is illus trated in FIGURE 4 wherein an injector 62 is illustrated having a head portion 64 which is elongated and is formed with a collar -S around the upper end thereof corresponding substantially to the collar 40 on the plunger 38 as shown in the apparatus illustrated in FIGURE 1. The upper end of the head portion 64 is formed with a centrally extending rod 68 which is adapted to centrally guide and align a coil spring such as the spring 34 shown in FIGURE 1 disposed in resilient bearing contact against the ejector.

Still another alternate satisfactory version of the ejector mechanism is illustrated in FIGURE 5 wherein the plunger 38 (FIG. 1) or extension (FIG. 4) between the ejector and spring has been eliminated by employing a coil spring 74 having a conically wound or otherwise reduced diameter lower end which is adapted to be seated in bearing contact directly against the upper end portion of the head 72 of an ejector 74. The head 72 of the ejector 74 is formed with an upwardly extending rod 75 which is adapted to centrally align the lower end of the coil spring 70 with the sleeve 46. In each of the versions as shown in FIGURES 1-5, suitable coasting means such as the cams 48, 50, 52 and 52. are employed which are adapted to selectively engage and retain the ejector in the retracted position as desired.

In the specific construction as shown in FIGURES 1, 2 and 5, the sleeve 46 comprises a separate component which is securely fastened within the lower end of the bore 24 to prevent relative axial movement tlierebetween. The sleeve 46 as well as the ejector 23 may be made of a suitable synthetic plastic material which may additionally incorporate filler and reinforcing materials therein to provide the requisite wear resistance and strength. The sleeve may be adhesively secured within the bore such as by means of an adhesive indicated generally at '76. Alternatively, the sleeve and ejector may be comprised of a sintered metallic body and the sleeve brazed or otherwise securely fastened within the bore.

While it will be apparent that the preferred embodiments herein illustrated are Well calculated to fulfill the objects above stated, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoined claims.

What is claimed is:

1. A pierce punch including a body formed with a first bore extending inwardly from the cutting face thereof and a second bore of enlarged diameter disposed in aligned communication with said first bore and forming an annular shoulder at the juncture therebetween, an ejector comprising an elongated pin having an enlarged head at one end thereof slidably disposed in said first and said second bore for reciprocating movement to and from a projected position wherein the end of said pin projects beyond said cutting face and a retracted position wherein said end is within said body, resilient means for urging said ejector toward said projected position, and coacting means including first carn means disposed in circumferentially spaced relationship on said head and second cams means disposed in longitudinally spaced rows and circumferentially spaced relationship around said second bore for rotatably indexing said ejector and said first cam means therein to and from engagement with said second cam means and alternately maintaining said pin in said retracted position in response to alternate movements of said ejector inwardly to a position wherein the end of said pin is moved to a preselected distance inwardly beyond said cutting face.

2. A pierce punch including a body formed with a first bore extending inwardly from the cutting face thereof and a second bore of enlarged diameter disposed in aligned communication with said first bore and forming an annular shoulder at the juncture therebetween, an ejector comprising an elongated pin having an enlarged head at one end thereof slidably disposed in said first and said second bore for reciprocating movement to and from a projected position wherein the end of said pin projects beyond said cutting face and a retracted position wherein said end is within said body, resilient means for urging said ejector toward said projected position, and coacting means on said head and around said second bore for releasably engaging said ejector and maintaining said pin in said retracted position in response to alternate movements of said ejector inwardly wherein the end of said pin is moved a preselected distance inwardly beyond said cutting face, said coacting means comprising a plurality of radially extending circumferentially spaced earns on said head, a first series and a second series of inwardly extending and circumferentially spaced cams disposed in longitudinally spaced relationship around said second bore and positioned in camrning relationship relative to said cams on said head for effecting rotary indexing of said ejector to and from en engaged and disengaged condition therewith.

No references cited.

WILLIAM 1V. DYER, In, Primary Examiner.

WILLIAM S. LAWSON, Examiner. 

1. A PIERCE PUNCH INCLUDING A BODY FORMED WITH A FIRST BORE EXTENDING INWARDLY FROM THE CUTTING FACE THEREOF AND A SECOND BORE OF ENLARGED DIAMETER DISPOSED IN ALIGNED COMMUNICATION WITH SAID FIRST BORE AND FORMING AN ANNULAR SHOULDER AT THE JUNCTURE THEREBETWEEN, AN EJECTOR COMPRISING AN ELONGATED PIN HAVING AN ENLARGED HEAD AT ONE END THEREOF SLIDABLY DISPOSED IN SAID FIRST AND SAID SECOND BORE FOR RECIPROCATING MOVEMENT TO AND FROM A PROJECTED POSITION WHEREIN THE END OF SAID PIN PROJECTS BEYOND SAID CUTTING FACE AND A RETRACTED POSITION WHEREIN SAID END IS WITHIN SAID BODY, RESILIENT MEANS FOR URGING SAID EJECTOR TOWARD SAID PROJECTED POSITION, AND CONTACTING MEANS INCLUDING FIRST CAM MEANS DISPOSED IN CIRCUMFERENTIALLY SPACED RELATIONSHIP ON SAID HEAD AND SECOND CAMS MEANS DISPOSED IN LONGITUDINAL SPACED ROWS AND CIRCUMFERENTIALLY SPACED RELATIONSHIP AROUND SAID SECOND BORE FOR ROTATABLY INDEXING SAID EJECTOR AND SAID FIRST CAM MEANS THEREIN TO AND FROM ENGAGEMENT WITH SAID SECOND CAM MEANS AND ALTERNATELY MAINTAINING SAID PIN IN SAID RETRACTED POSITION IN RESPONSE TO ALTERNATE MOVEMENTS OF SAID EJECTOR INWARDLY TO A POSITION WHEREIN THE END OF SAID PIN IS MOVED TO A PRESELECTED DISTANCE INWARDLY BEYOND SAID CUTTING FACE. 